(Photograph = Oreocereus celsianus, Sebastian Santecchia)

Introduction

Oreocereus celsianus is a columnar cactus of the in the high Andes of Bolivia, Peru, and northern Argentina. Scientists wanted to know what animal pollinated O. celsianus. Was it a bat as would be expected in the case of many North American columnar cacti?

The Details

O. celsianus grows to 20-ft tall. Its high-perched flowers could easily be approached by insects, birds, or bats. However, it has red, tubular flowers, which suggest that they might be adapted to attract birds. It produces large amounts of nectar, which suggests that a bird or bat might be the pollinator.

Butterflies, flies, bees, and moths were all observed to visit O. celsianus flowers. Bats were not observed. Hummingbirds were the most important visitors. The Giant Hummingbird (Patagona gigas), the Wedge-tailed Hillstar (Oreotrochilus adela) and the Sparkling Violetear (Colibri corusans) were the three most common hummingbirds in the area and all visited the flowers. But, the Giant Hummingbird was by far the most common visitor.

It was concluded that the main pollinator of O. celsianus in the study area was the Giant Hummingbird and that bats and insects played no role.

Additional Reading: Pollination Biology of Oreocereus celsianus